Australia's biggest attraction is the Great Barrier Reef, one of the wonders of the natural world. The reef covers about 300,000 square kilometres and is home to many amazing animals and plants. Although you're allowed to swim and dive on the Barrier Reef, you have to be careful as some of its residents are not very friendly!
Stonefish
The stonefish looks like a stone, just like the reef that it lives on. It also likes to sit on sandy It has spines, though, the seabed. that it uses to defend itself. They are very sharp and contain a nasty venom which can be very painful and sometimes lethal. To avoid the stonefish's nasty sting, you mustn't touch the reef while swimming and you should make sure you always wear shoes or sandals when walking in shallow, sandy water
Irukandji jellyfish
These tiny jellyfish are the size of your thumbnail and impossible to see in the water. Don't be tricked, though, by their size! They are one of the most poisonous animals on the planet and a sting from one of them causes terrible symptoms that unless treated properly might kill you.
Cone shells
If you collect shells, you'll really appreciate these attractive colourful cone shells but be careful! They are really snaillike creatures that can give you a toxic and painful sting. If one of these innocent-looking creatures stings you, you must get to the nearest hospital as soon as possible!
Sharks
Many different sharks live on the Great Barrier Reef, but few are dangerous to humans. 35 Shark attacks occur rarely. Still, some attacks are fatal so you should always swim, dive or surf with other people and you mustn't swim at dusk or at dawn, which is shark feeding time.